Improvement in steam-engine pistons



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ALEXANDER NADOW, OF SPRINGFIELD, MASSACHUSETTS.

I Letters Patent No. 73,456, dated January 21, 1868.

IMPROVEMENT m STEAM-ENGINE PISTONS.

TO ALL WHOM IT MAY CONCERN:

Be it known that 'I, ALEXANDER Nnnow, of Springfield, Hampden county,Commonwealth of Massachusetts, have invented certain Improvements in thePistons of Steam-Engines; and I do hereby declare that the following isafull and exact description thereof, reference being bad to theaccompanying drawings, and to the letters of reference marked thereon.In the drawings Figure 1 is longitudinal section of a steam-cylinder, A,.showing the piston B, as arranged in my invention. A J

Figure 2 is a eross-scction of the same, showing the piston B, with onehead, 0, removed.

Figure 3 is a section of the pistonQwiththc ring Z) removed; and

Figure 4, avicw of the piston, with the ring 6 removed.

The object'ot' my invention is to obtain a cheap and accurately-fittingpiston, which is packed or rendcred steam tight, by means of a ring, Z1,formed in two or more segments, and expanded against the inside of thecylinder by means of steam, which is let inside of the piston in apeculiar manner, or, if preferred, by means of a spring inside ofthepiston, the form of the ring and manner of letting the steam inside ofthe piston-being the improvements constituting this invention.

The construction is as follows: The outside ring I) of the piston Bisformed of two or more segmcnts,- C G, fig. 2,and fits over the piston,as shown in fig. 3, having two heads, a c. This ring, at the joints m m,is of peculiar form, as shown in 1, so as to allow it to spread outagainst the cylinder, for if the space d be made very much larger by theexpansion of the ring, no steam can get by, as it is stopped by the part8 of the joint, when the two parts of the ring are ground to an accuratefit.

Pistons, a s usually constructed, are made of.a number of rings, placedsidc'by side, and cut at only oneplace in each ring, and placed on thepiston so as to break joints, or else are made of a great number ofsegments, also brcakingjoints. New, in the first case, any expansion ofthe rings throws them greatly out of the form of a true circle, thusmaking an inaccurate fit in the cylinder, and in the second case, theyare very expensive. New, in my invention, only one ring is used, withjoints, as described, made in two, or at most, three segments, though Ido not. wish to confine myself to any particular number, and thus formsa very cheap and durable; ring, and also, when expanded, it fits thecylinder much better than a ring out in only one place.

I Inside ofthis packing-ring is a double ring, of thin metal, ff, whichserves for the steam to act against when let inside of the piston, as Iwill now describe. 9 is a valve hung on a pivot, at 11. Under each end,of this valve is aport, 7a is, communicating with the cylinder at eachside of the piston. Now as steam is let on at one side er the piston itenters at this port, it, and blows up into the inside of the-piston, andas it does this, the valve 9 isimoved so as to cover the port it, andthus preventing the steam from blowing through the piston. As the steamcomes inside of the piston, it acts onff, the thin metal ring spoken of,and forces it out against .the packing-ring 6, which isforccd againstthe inside of the cylinder, thus packing the piston.

One objection to self or steam-packing pistons has been that theyrequired so much room for expansion, that when used without steam, as inthe case of a. locomotive going down a grade, all the ports being loose,would lie on the bottom of the. cylinder, and thus wear it out of acircular form, but in this arrangement, so little room is required thata very small amount of space between the packing-ring and the cylinderis necessary, thus obviating this difficulty. The simplicity of thisarrangement makes it nearly impossible to be got out of order, while thetwo great requirements, eheapncss and durability, are at the same timecombined with this simplicity.

New, having described my invention, what I claim as new, and desire tosecure by Letters Patent, is-- The valve y, when used in combinationwith the piston 13 and ports 7c is, substantially-as described.

ALEXANDER NADOW.

Witnesses:

J. 'B'. 'GARDINER, MILTON BRADLEY.

